The invention relates to built-in connector elements for sandwich type compound panels, particularly for panels having a honeycomb core enclosed between two outer cover layers. The connector element is provided with a threaded hole for receiving other connecting elements. The built-in element is held in position in the panel by means of a curable, pourable resin mass and by its anchoring means.
German Patent Publication (DE-AS) No. 1,400,888 describes a built-in element of this type. Such built-in element is referred to as a dowel and comprises a cylindrical body with a dead-end hole. A head flange and a bottom flange are secured to the cylindrical body. The dowel head comprises three anchoring teeth distributed about the circumference. These teeth are supposed to be pressed into the cover layer when the element is installed. The dowel foot has one or several flattened zones, the surfaces of which are supposed to form with the pourable resin mass after its curing a safety catch against torsion loads. Two bores are arranged in the dowel head. One bore serves for introducing the pourable resin mass and the other bore serves for venting and overflow. This type of dowel may be manufactured only at substantial expense and requires several mechanical manufacturing steps. Even if the blank for the dowel is produced, for example as a cast part, it is still necessary to machine at least the two flanges and a ring groove and to drill the two bores in the dowel head and last, but not least, to produce the teeth. The casting itself is also involved because a divided mold is required due to the two flanges.